Recently, a data write method called “shingled write,” which can write data on a disk with a high recording density, has been developed in the field of hard disk drives (hereinafter referred to as “disk drives” in some cases). This method is also known as the “overlapped write method.”
In such a write method, data is written on a disk, forming data tracks not spaced apart at all, or rather each track partly overlapping either adjacent track. In other words, the tracks are arranged at a high density on the disk.
In the shingled write method, the write head tracks data tracks one after another, writing data on the disk, while moving in the radial direction of a spinning disk. Therefore, while the write head is writing data in one track, it writes the data also in a part of the immediately preceding track. Hence, data should be written with a specific margin in order to secure an effective area in the preceding data track and to maintain a sufficient recording performance. If the margin is too large, however, the tracks will inevitably be arranged at a lower density on the disk.